One of our servers is an EC2 instance hosted on AWS. For some reason, pure-ftpd connections do not work. Logins are successful but upon trying to retrieve the directory listing it hits a timeout every time.

Firewalld is configured to allow passive mode. Even with the firewall off it is still an issue. And I've verified that:

ForcePassiveIP: xxx.xxx.xxx.xxx
Is set in /var/cpanel/conf/pureftpd/main